import com.fasterxml.jackson.databind.ObjectMapper;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: lishuo
 * Date: 2023-08-12
 * Time: 15:43
 */
class Message {
    public String from;
    public String to;
    public String meg;

    @Override
    public String toString() {
        return "Message{" +
                "from='" + from + '\'' +
                ", to='" + to + '\'' +
                ", meg='" + meg + '\'' +
                '}';
    }
}
@WebServlet("/love")
public class MessageServlet extends HttpServlet {
    // 用来存储消息的数组
    private List<Message> messages = new ArrayList<>();
    // 构造json的对象
    private ObjectMapper objectMapper = new ObjectMapper();

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // 这个方法来处理 “获取所有留言消息”
        // 需要返回一个json字符串数组，jackson直接帮我们处理好了格式
        String respString = objectMapper.writeValueAsString(messages);
        resp.setContentType("application/json;charset=utf8");
        resp.getWriter().write(respString);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        // 这个方法用来处理 “提交新消息”
        Message message = objectMapper.readValue(req.getInputStream(),Message.class);
        messages.add(message);

        // 可以打印一下提交日志
        System.out.println(message);

        // 此时响应的body为空，不需要额外处理，默认返回200报文
    }
}
